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/* * Copyright (C) 2008 The Guava Authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.google.common.primitives; import static com.google.common.base.Preconditions.checkArgument; import static com.google.common.base.Preconditions.checkElementIndex; import static com.google.common.base.Preconditions.checkNotNull; import static com.google.common.base.Preconditions.checkPositionIndexes; import com.google.common.annotations.Beta; import com.google.common.annotations.GwtCompatible; import com.google.common.base.Converter; import java.io.Serializable; import java.util.AbstractList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.RandomAccess; import javax.annotation.CheckForNull; import javax.annotation.CheckReturnValue; import javax.annotation.Nullable; /** * Static utility methods pertaining to {@code long} primitives, that are not * already found in either {@link Long} or {@link Arrays}. * * <p>See the Guava User Guide article on <a href= * "https://github.com/google/guava/wiki/PrimitivesExplained"> * primitive utilities</a>. * * @author Kevin Bourrillion * @since 1.0 */ @CheckReturnValue @GwtCompatible public final class Longs { private Longs() { } /** * The number of bytes required to represent a primitive {@code long} * value. */ public static final int BYTES = Long.SIZE / Byte.SIZE; /** * The largest power of two that can be represented as a {@code long}. * * @since 10.0 */ public static final long MAX_POWER_OF_TWO = 1L << (Long.SIZE - 2); /** * Returns a hash code for {@code value}; equal to the result of invoking * {@code ((Long) value).hashCode()}. * * <p>This method always return the value specified by {@link * Long#hashCode()} in java, which might be different from * {@code ((Long) value).hashCode()} in GWT because {@link Long#hashCode()} * in GWT does not obey the JRE contract. * * @param value a primitive {@code long} value * @return a hash code for the value */ public static int hashCode(long value) { return (int) (value ^ (value >>> 32)); } /** * Compares the two specified {@code long} values. The sign of the value * returned is the same as that of {@code ((Long) a).compareTo(b)}. * * <p><b>Note for Java 7 and later:</b> this method should be treated as * deprecated; use the equivalent {@link Long#compare} method instead. * * @param a the first {@code long} to compare * @param b the second {@code long} to compare * @return a negative value if {@code a} is less than {@code b}; a positive * value if {@code a} is greater than {@code b}; or zero if they are equal */ public static int compare(long a, long b) { return (a < b) ? -1 : ((a > b) ? 1 : 0); } /** * Returns {@code true} if {@code target} is present as an element anywhere in * {@code array}. * * @param array an array of {@code long} values, possibly empty * @param target a primitive {@code long} value * @return {@code true} if {@code array[i] == target} for some value of {@code * i} */ public static boolean contains(long[] array, long target) { for (long value : array) { if (value == target) { return true; } } return false; } /** * Returns the index of the first appearance of the value {@code target} in * {@code array}. * * @param array an array of {@code long} values, possibly empty * @param target a primitive {@code long} value * @return the least index {@code i} for which {@code array[i] == target}, or * {@code -1} if no such index exists. */ public static int indexOf(long[] array, long target) { return indexOf(array, target, 0, array.length); } // TODO(kevinb): consider making this public private static int indexOf(long[] array, long target, int start, int end) { for (int i = start; i < end; i++) { if (array[i] == target) { return i; } } return -1; } /** * Returns the start position of the first occurrence of the specified {@code * target} within {@code array}, or {@code -1} if there is no such occurrence. * * <p>More formally, returns the lowest index {@code i} such that {@code * java.util.Arrays.copyOfRange(array, i, i + target.length)} contains exactly * the same elements as {@code target}. * * @param array the array to search for the sequence {@code target} * @param target the array to search for as a sub-sequence of {@code array} */ public static int indexOf(long[] array, long[] target) { checkNotNull(array, "array"); checkNotNull(target, "target"); if (target.length == 0) { return 0; } outer: for (int i = 0; i < array.length - target.length + 1; i++) { for (int j = 0; j < target.length; j++) { if (array[i + j] != target[j]) { continue outer; } } return i; } return -1; } /** * Returns the index of the last appearance of the value {@code target} in * {@code array}. * * @param array an array of {@code long} values, possibly empty * @param target a primitive {@code long} value * @return the greatest index {@code i} for which {@code array[i] == target}, * or {@code -1} if no such index exists. */ public static int lastIndexOf(long[] array, long target) { return lastIndexOf(array, target, 0, array.length); } // TODO(kevinb): consider making this public private static int lastIndexOf(long[] array, long target, int start, int end) { for (int i = end - 1; i >= start; i--) { if (array[i] == target) { return i; } } return -1; } /** * Returns the least value present in {@code array}. * * @param array a <i>nonempty</i> array of {@code long} values * @return the value present in {@code array} that is less than or equal to * every other value in the array * @throws IllegalArgumentException if {@code array} is empty */ public static long min(long... array) { checkArgument(array.length > 0); long min = array[0]; for (int i = 1; i < array.length; i++) { if (array[i] < min) { min = array[i]; } } return min; } /** * Returns the greatest value present in {@code array}. * * @param array a <i>nonempty</i> array of {@code long} values * @return the value present in {@code array} that is greater than or equal to * every other value in the array * @throws IllegalArgumentException if {@code array} is empty */ public static long max(long... array) { checkArgument(array.length > 0); long max = array[0]; for (int i = 1; i < array.length; i++) { if (array[i] > max) { max = array[i]; } } return max; } /** * Returns the values from each provided array combined into a single array. * For example, {@code concat(new long[] {a, b}, new long[] {}, new * long[] {c}} returns the array {@code {a, b, c}}. * * @param arrays zero or more {@code long} arrays * @return a single array containing all the values from the source arrays, in * order */ public static long[] concat(long[]... arrays) { int length = 0; for (long[] array : arrays) { length += array.length; } long[] result = new long[length]; int pos = 0; for (long[] array : arrays) { System.arraycopy(array, 0, result, pos, array.length); pos += array.length; } return result; } /** * Returns a big-endian representation of {@code value} in an 8-element byte * array; equivalent to {@code ByteBuffer.allocate(8).putLong(value).array()}. * For example, the input value {@code 0x1213141516171819L} would yield the * byte array {@code {0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19}}. * * <p>If you need to convert and concatenate several values (possibly even of * different types), use a shared {@link java.nio.ByteBuffer} instance, or use * {@link com.google.common.io.ByteStreams#newDataOutput()} to get a growable * buffer. */ public static byte[] toByteArray(long value) { // Note that this code needs to stay compatible with GWT, which has known // bugs when narrowing byte casts of long values occur. byte[] result = new byte[8]; for (int i = 7; i >= 0; i--) { result[i] = (byte) (value & 0xffL); value >>= 8; } return result; } /** * Returns the {@code long} value whose big-endian representation is * stored in the first 8 bytes of {@code bytes}; equivalent to {@code * ByteBuffer.wrap(bytes).getLong()}. For example, the input byte array * {@code {0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19}} would yield the * {@code long} value {@code 0x1213141516171819L}. * * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that * library exposes much more flexibility at little cost in readability. * * @throws IllegalArgumentException if {@code bytes} has fewer than 8 * elements */ public static long fromByteArray(byte[] bytes) { checkArgument(bytes.length >= BYTES, "array too small: %s < %s", bytes.length, BYTES); return fromBytes(bytes[0], bytes[1], bytes[2], bytes[3], bytes[4], bytes[5], bytes[6], bytes[7]); } /** * Returns the {@code long} value whose byte representation is the given 8 * bytes, in big-endian order; equivalent to {@code Longs.fromByteArray(new * byte[] {b1, b2, b3, b4, b5, b6, b7, b8})}. * * @since 7.0 */ public static long fromBytes(byte b1, byte b2, byte b3, byte b4, byte b5, byte b6, byte b7, byte b8) { return (b1 & 0xFFL) << 56 | (b2 & 0xFFL) << 48 | (b3 & 0xFFL) << 40 | (b4 & 0xFFL) << 32 | (b5 & 0xFFL) << 24 | (b6 & 0xFFL) << 16 | (b7 & 0xFFL) << 8 | (b8 & 0xFFL); } private static final byte[] asciiDigits = createAsciiDigits(); private static byte[] createAsciiDigits() { byte[] result = new byte[128]; Arrays.fill(result, (byte) -1); for (int i = 0; i <= 9; i++) { result['0' + i] = (byte) i; } for (int i = 0; i <= 26; i++) { result['A' + i] = (byte) (10 + i); result['a' + i] = (byte) (10 + i); } return result; } private static int digit(char c) { return (c < 128) ? asciiDigits[c] : -1; } /** * Parses the specified string as a signed decimal long value. The ASCII * character {@code '-'} (<code>'\u002D'</code>) is recognized as the * minus sign. * * <p>Unlike {@link Long#parseLong(String)}, this method returns * {@code null} instead of throwing an exception if parsing fails. * Additionally, this method only accepts ASCII digits, and returns * {@code null} if non-ASCII digits are present in the string. * * <p>Note that strings prefixed with ASCII {@code '+'} are rejected, even * under JDK 7, despite the change to {@link Long#parseLong(String)} for * that version. * * @param string the string representation of a long value * @return the long value represented by {@code string}, or {@code null} if * {@code string} has a length of zero or cannot be parsed as a long * value * @since 14.0 */ @Beta @Nullable @CheckForNull public static Long tryParse(String string) { return tryParse(string, 10); } /** * Parses the specified string as a signed long value using the specified * radix. The ASCII character {@code '-'} (<code>'\u002D'</code>) is * recognized as the minus sign. * * <p>Unlike {@link Long#parseLong(String, int)}, this method returns * {@code null} instead of throwing an exception if parsing fails. * Additionally, this method only accepts ASCII digits, and returns * {@code null} if non-ASCII digits are present in the string. * * <p>Note that strings prefixed with ASCII {@code '+'} are rejected, even * under JDK 7, despite the change to {@link Long#parseLong(String, int)} * for that version. * * @param string the string representation of an long value * @param radix the radix to use when parsing * @return the long value represented by {@code string} using * {@code radix}, or {@code null} if {@code string} has a length of zero * or cannot be parsed as a long value * @throws IllegalArgumentException if {@code radix < Character.MIN_RADIX} or * {@code radix > Character.MAX_RADIX} * @since 19.0 */ @Beta @Nullable @CheckForNull public static Long tryParse(String string, int radix) { if (checkNotNull(string).isEmpty()) { return null; } if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX) { throw new IllegalArgumentException("radix must be between MIN_RADIX and MAX_RADIX but was " + radix); } boolean negative = string.charAt(0) == '-'; int index = negative ? 1 : 0; if (index == string.length()) { return null; } int digit = digit(string.charAt(index++)); if (digit < 0 || digit >= radix) { return null; } long accum = -digit; long cap = Long.MIN_VALUE / radix; while (index < string.length()) { digit = digit(string.charAt(index++)); if (digit < 0 || digit >= radix || accum < cap) { return null; } accum *= radix; if (accum < Long.MIN_VALUE + digit) { return null; } accum -= digit; } if (negative) { return accum; } else if (accum == Long.MIN_VALUE) { return null; } else { return -accum; } } private static final class LongConverter extends Converter<String, Long> implements Serializable { static final LongConverter INSTANCE = new LongConverter(); @Override protected Long doForward(String value) { return Long.decode(value); } @Override protected String doBackward(Long value) { return value.toString(); } @Override public String toString() { return "Longs.stringConverter()"; } private Object readResolve() { return INSTANCE; } private static final long serialVersionUID = 1; } /** * Returns a serializable converter object that converts between strings and * longs using {@link Long#decode} and {@link Long#toString()}. * * @since 16.0 */ @Beta public static Converter<String, Long> stringConverter() { return LongConverter.INSTANCE; } /** * Returns an array containing the same values as {@code array}, but * guaranteed to be of a specified minimum length. If {@code array} already * has a length of at least {@code minLength}, it is returned directly. * Otherwise, a new array of size {@code minLength + padding} is returned, * containing the values of {@code array}, and zeroes in the remaining places. * * @param array the source array * @param minLength the minimum length the returned array must guarantee * @param padding an extra amount to "grow" the array by if growth is * necessary * @throws IllegalArgumentException if {@code minLength} or {@code padding} is * negative * @return an array containing the values of {@code array}, with guaranteed * minimum length {@code minLength} */ public static long[] ensureCapacity(long[] array, int minLength, int padding) { checkArgument(minLength >= 0, "Invalid minLength: %s", minLength); checkArgument(padding >= 0, "Invalid padding: %s", padding); return (array.length < minLength) ? copyOf(array, minLength + padding) : array; } // Arrays.copyOf() requires Java 6 private static long[] copyOf(long[] original, int length) { long[] copy = new long[length]; System.arraycopy(original, 0, copy, 0, Math.min(original.length, length)); return copy; } /** * Returns a string containing the supplied {@code long} values separated * by {@code separator}. For example, {@code join("-", 1L, 2L, 3L)} returns * the string {@code "1-2-3"}. * * @param separator the text that should appear between consecutive values in * the resulting string (but not at the start or end) * @param array an array of {@code long} values, possibly empty */ public static String join(String separator, long... array) { checkNotNull(separator); if (array.length == 0) { return ""; } // For pre-sizing a builder, just get the right order of magnitude StringBuilder builder = new StringBuilder(array.length * 10); builder.append(array[0]); for (int i = 1; i < array.length; i++) { builder.append(separator).append(array[i]); } return builder.toString(); } /** * Returns a comparator that compares two {@code long} arrays * lexicographically. That is, it compares, using {@link * #compare(long, long)}), the first pair of values that follow any * common prefix, or when one array is a prefix of the other, treats the * shorter array as the lesser. For example, * {@code [] < [1L] < [1L, 2L] < [2L]}. * * <p>The returned comparator is inconsistent with {@link * Object#equals(Object)} (since arrays support only identity equality), but * it is consistent with {@link Arrays#equals(long[], long[])}. * * @see <a href="http://en.wikipedia.org/wiki/Lexicographical_order"> * Lexicographical order article at Wikipedia</a> * @since 2.0 */ public static Comparator<long[]> lexicographicalComparator() { return LexicographicalComparator.INSTANCE; } private enum LexicographicalComparator implements Comparator<long[]> { INSTANCE; @Override public int compare(long[] left, long[] right) { int minLength = Math.min(left.length, right.length); for (int i = 0; i < minLength; i++) { int result = Longs.compare(left[i], right[i]); if (result != 0) { return result; } } return left.length - right.length; } } /** * Returns an array containing each value of {@code collection}, converted to * a {@code long} value in the manner of {@link Number#longValue}. * * <p>Elements are copied from the argument collection as if by {@code * collection.toArray()}. Calling this method is as thread-safe as calling * that method. * * @param collection a collection of {@code Number} instances * @return an array containing the same values as {@code collection}, in the * same order, converted to primitives * @throws NullPointerException if {@code collection} or any of its elements * is null * @since 1.0 (parameter was {@code Collection<Long>} before 12.0) */ public static long[] toArray(Collection<? extends Number> collection) { if (collection instanceof LongArrayAsList) { return ((LongArrayAsList) collection).toLongArray(); } Object[] boxedArray = collection.toArray(); int len = boxedArray.length; long[] array = new long[len]; for (int i = 0; i < len; i++) { // checkNotNull for GWT (do not optimize) array[i] = ((Number) checkNotNull(boxedArray[i])).longValue(); } return array; } /** * Returns a fixed-size list backed by the specified array, similar to {@link * Arrays#asList(Object[])}. The list supports {@link List#set(int, Object)}, * but any attempt to set a value to {@code null} will result in a {@link * NullPointerException}. * * <p>The returned list maintains the values, but not the identities, of * {@code Long} objects written to or read from it. For example, whether * {@code list.get(0) == list.get(0)} is true for the returned list is * unspecified. * * @param backingArray the array to back the list * @return a list view of the array */ public static List<Long> asList(long... backingArray) { if (backingArray.length == 0) { return Collections.emptyList(); } return new LongArrayAsList(backingArray); } @GwtCompatible private static class LongArrayAsList extends AbstractList<Long> implements RandomAccess, Serializable { final long[] array; final int start; final int end; LongArrayAsList(long[] array) { this(array, 0, array.length); } LongArrayAsList(long[] array, int start, int end) { this.array = array; this.start = start; this.end = end; } @Override public int size() { return end - start; } @Override public boolean isEmpty() { return false; } @Override public Long get(int index) { checkElementIndex(index, size()); return array[start + index]; } @Override public boolean contains(Object target) { // Overridden to prevent a ton of boxing return (target instanceof Long) && Longs.indexOf(array, (Long) target, start, end) != -1; } @Override public int indexOf(Object target) { // Overridden to prevent a ton of boxing if (target instanceof Long) { int i = Longs.indexOf(array, (Long) target, start, end); if (i >= 0) { return i - start; } } return -1; } @Override public int lastIndexOf(Object target) { // Overridden to prevent a ton of boxing if (target instanceof Long) { int i = Longs.lastIndexOf(array, (Long) target, start, end); if (i >= 0) { return i - start; } } return -1; } @Override public Long set(int index, Long element) { checkElementIndex(index, size()); long oldValue = array[start + index]; // checkNotNull for GWT (do not optimize) array[start + index] = checkNotNull(element); return oldValue; } @Override public List<Long> subList(int fromIndex, int toIndex) { int size = size(); checkPositionIndexes(fromIndex, toIndex, size); if (fromIndex == toIndex) { return Collections.emptyList(); } return new LongArrayAsList(array, start + fromIndex, start + toIndex); } @Override public boolean equals(@Nullable Object object) { if (object == this) { return true; } if (object instanceof LongArrayAsList) { LongArrayAsList that = (LongArrayAsList) object; int size = size(); if (that.size() != size) { return false; } for (int i = 0; i < size; i++) { if (array[start + i] != that.array[that.start + i]) { return false; } } return true; } return super.equals(object); } @Override public int hashCode() { int result = 1; for (int i = start; i < end; i++) { result = 31 * result + Longs.hashCode(array[i]); } return result; } @Override public String toString() { StringBuilder builder = new StringBuilder(size() * 10); builder.append('[').append(array[start]); for (int i = start + 1; i < end; i++) { builder.append(", ").append(array[i]); } return builder.append(']').toString(); } long[] toLongArray() { // Arrays.copyOfRange() is not available under GWT int size = size(); long[] result = new long[size]; System.arraycopy(array, start, result, 0, size); return result; } private static final long serialVersionUID = 0; } }